Engine valve mounting



P 10, I I F. G. HOBART 1 2,407,422

I ENGINE VALVE MOUNTING Filed Aug. 30, 1945 2 Sheets-Sheet 1 I N VEN 711m KLIN G. HOBART Sept. 10, 1946. F, G, HOBART I 2,407,422

ENGINE VALVE MdUNTING Filed Aug. 50, 1945 2 Sheets-Sheet 2 .I /v vsvvrore FRANKLIN G. HOBART Arm/av Patented Sept. 10, 1946 ENGINE VALVE MQUNTING Franklin G. Hobart, Beloit, Wis., assignor to Fairbanks, Morse & 00., Chicago, 111., a corporation of Illinoi Application August so, 1945, Serial No. 613,542,

Thisinvention relates to'i-mprovements in internal combustion engines, and has particular reference to improvements in the arrangement and operative mounting of engine valves.

A principal object of the present invention is to afford an improved engine valve mounting arrangement which is suitable in particular to cam actuated, cylinder fuel inlet and exhaust valves for internal combustion engines of the L-head type, the present improvements providing for valve actuation by a cam and cam-follower or valve tappet assembly, and valve loading means all located in the engine crankcase in a position of ready accessibility therein, and an improved arrangement of valve mounting such as to facilitate machining and assembly operations relative to the valve supporting means of the invention.

Another object of the present invention is to provide a valve stem compartment or housing preferably formed as an integral part of the engine cylinder frame, the housing affording relatively spaced tapered seats for valve stem bushings, and the arrangement thereof being such as to provide for insertion of the bushingsfrom one end of the housing into assembly position in the housing seats, and permitting removal of the bushings from the same end of the housing.

Other objects and advantages of the present invention will appear readily from the following description of a preferred embodiment of the invention as illustrated in the accompanying drawings, wherein:

Fig. 1 is a longitudinal sectional elevation vertically through an internal combustion engine of a horizontal cylinder type, illustrating the presently improved provisions for mounting the engine valves;

Fig. 2 is a somewhat enlarged, fragmentary longitudinal sectional elevation of the engine as taken in a plane displaced 90 from the plane of Fig. 1, as along line 22 in Fig, 1, and

Fig 3 is a fragmentary sectional view of the engine in the valve mounting zone thereof, illustrating a modification of the cam follower guide means. 7

While the present invention is applicable generally to engines of various types, nevertheless for the purpose of present disclosure, it is preferred to show the present improvements in connection with an L-head type engine having its cylinder or cylinders in a horizontal position.

Referring now to the drawings by suitable characters of reference, theengine shown includes an engine frame providing a horizontal cylinder Claims. (Cl. 12390) II and surrounding water jacket l2. Associated with the engine cylinder frame is a crankcase I4 which as shown, is open at its upper end l5 for access to the interior of the crankcase and to parts of the valve mechanism as will presently appear. The opening l5 normally is closed by a crankcase cover IS.

A pair of valve housings l8 and I 9 (Fig. 2) each formed by preference as an integral part of the cylinder frame It, are arranged longitudinally of the cylinder H thereabove, and within the cylinder jacket space I 2, and each has a length substantially co-extensive with the length of the cylinder. The housings l8 and I9 preferably are of tubular form and are adapted at their corresponding ends and 22 adjacent the head end of the cylinder, to provide valve seats 23 and 24, the opposite ends 26 and 21 of the housings being open to the crankcase. Overlying the head end of the cylinder and the valve seats 23 and 24 is a cylinder head 28 which as appears, is formed to provide a chamber 30 communicating the cylinder with the openings at the valve seats. As appears in Fig. 2, the housings l8 and I9 are arranged in parallel above cylinder ll, housing [8 being provided for the engine inlet valve 3| and housing i9 for the engine exhaust valve 32. Since each of the presently improved inlet and exhaust valve assemblies are substantially identical in structure and arrangement, only one thereof will be hereinafter described in detail, the same characters of reference differentiated by letter suffix a, being applied to the corresponding parts of the other assembly.

Within the housing l8 and near-the valve seat end 20 thereof, is an annular projection or boss 34,'the surface of which is tapered by a predetermined degree convergently toward the crankcase end of the housing, the degree of taper here preferred being of the order of 2 degrees. Inwardly of housing l8 near the crankcase end 26 thereof, is a further annular projection or boss the surface of which is tapered to a similar degree and in the same direction. The tapered surfaces of bosses 34 and 35 provide mounting seats for externally tapered valve guide bushings 36 and 38 respectively, the bushings affording an operative support for thestem 39 of the valve 3| in control of the opening through valve seat 23. Stem 3B is projected beyond the housing end 26 and is provided with a spring abutment 40 against which abuts one end of a spring encircling the stem, the opposite end of the spring abutting a washer element 43 located in the hous ing [8 against shoulder 44 provided by boss 35.

In axial alignment with the valve stem is a cam follower or tappet member 46, which is slidably mounted in a follower support 41 carried by the crankcase, the follower being adapted for enga ment by a valve cam 48 on cam shaft 50, the latter being suitably driven from the engine crank shaft 5|. The operative engagement between the follower 46 and the free end of the valve stem 39 is adjustable through an abutment screw 52 threaded in follower 4B and locked in adjusted position by lock nut 54.

From the foregoing it will appear that according to the arrangement as thus far described, the valve spring 42, follower contact adjustment 52, and the follower 46 are all readily accessible, as for inspection, repair or replacement of these parts, through the crankcase opening l5, It will appear further that mounting or removal of the valve 3| relative to housing l8, may be readily effected from the head end of the cylinder upon removal of the cylinder head 28 and the valve loading spring 42.

An important feature of the present invention concerns the location and manner of mounting the bushings 36 and 38 in housing l8. The tapered seat 35 is formed such that the maximum diameter thereof is less than the minimum diameter in the convergent end of the tapered seat 34. Thus it will appear that bushing 38 may be inserted from the end E9 of the housing, through seat 34, and then frictionally engaged in seat 35. Whereupon bushing 36 may be in serted in seat 34. Removal of the bushings when desired or necessary, may be equally readily accomplished by driving the bushing 38 out of its seat 35 by any suitable means inserted in the housing from the crankcase end thereof, following which the bushing 36 (through the interposition of bushing 38) may be similarly driven out of its seat from the same end of the housing. A further important advantage of the present valve mounting arrangement is that it facilitates Inachining of the tapered valve seat 23 and the surfaces of seats 34 and 3'5 from the head end N) of the housing.

As appears in Fig. 2, bushing 38 is provided with one or more longitudinal grooves 56 which afford lubricant passage from the crankcase to the interior of the housing 8 for the lubrication of the valve stem 39 and bearing surfaces of the bushings 36 and 36. Also and as shown by Fig. 2 in particular; a conduit 58 opens laterally from the housing i8 adjacent the inlet valve 3! and through the outer wall of the cylinder frame ii) for connection to the source of engine fuel (not shown). The bushing 33 as appears, serves to close the conduit 58 to the interior of the housing on the crankcase side of the bushing. Similarly, a conduit 59 opening laterally of the housing E9 in the zone of exhaust valve 32, provides for exhaust discharge as through an exhaust manifold or pipe (not shown) connected to conduit 58. In thi instance also, the bushing 36a closes the exhaust conduit to the interior of hous ing !9 on the crankcase side of the bushing.

The valve mounting arrangement shown in the fragmentary view of Fig. 3, may be similar to that already described say for the valve stem 39, hence the same reference numerals apply to the corresponding part-s. However, the support 60 (corresponding generally to the support M) for the cam followers 46 and 46a (Fig. 2), is here shown as being carried by or integral with the cylinder frame H3. Accordingly and in order to reduce machining operations and any necessity for repositioning the cylinder frame for machining the guide surfaces of the support, as the guide surface 62 shown, the diameter of such guide surface is made slightly less than the min-. imum diameter of the tapered seat 35. Therefore, machining of the guide surface E52 may be done from the head end of the cylinder frame at the time the valve seat 23 and tapered bushing seats 34 and 35 are machined.

If preferred and as may be advantageous in the instance of small engines having relatively short length cylinders, the correspondingly shorter valve stems may be operatively supported each by but a single bushing element externally tapered and received in a tapered seat formed centrally in the stem housing, as the housing !8 or I9 in Fig. 2. For example, the bushing 36 associated with valve stem 39, could be employed alone in the smaller engine, with the tapered seat 34 therefore located preferably near the longitudinal center of the housing l8, while a like arrangement of bushing 35a and seat 34a would obtain in housing in. In this case, the single bushing supporting each valve stem, may be of somewhat increased axial length in order to assure suificient guiding support for the stem in valve operation.

Having now described the invention with regard to presently preferred embodiments thereof, it is to be understood that alteration or modifications of parts and the arrangement thereof, may be made without departing from the spirit and full intended scope of the invention as defined bythe appended claims.

I claim:

1. In an engine of the character described, providing a cylinder and crankcase assembly, the crankcase havin an access opening, a cylinder valve having a stem extending toward and terminating in an end section exposed in the crankcase near said access opening, means formed integral with the cylinder enclosing said valve stem between the valve thereof and said end section of the stem, said means providing a shoulder exposed in the crankcase, means providing a tapered seat in said enclosing means, an externally tapered guide bushing for said stem, removabiy received in said tapered seat, an abutment on said stem end section, and a valve closing spring effective between said abutment and said shou der, said spring being accessible through said crankcase access opening.

2. In an engine of the character described, a cylinder frame provided with a housing longitudinally of the frame, longitudinally spaced elements in said housing each having a tapered bore therethrough, the minimum diameter of one bore being greater than the maximum diameter of another of said tapered bores, tapered bushings seated in said bores, and a valve stem extending longitudinally in said housing and through said bushings.

3. In an engine of the character described, a frame providing a cylinder and a housing longitudinally of the cylinder, a cylinder head overlying one end of the cylinder and the corresponding end of said housing, said housing end being adapted as a valve seat, relatively spaced elements in said housing each providing a tapered bore therethrough, tapered bushings seated in said bores, the maximum diameter of one of said bushings being less than the minimum diameter of the tapered bore receiving another of the bushings, and a valve stemhaving a valve head cooperable with said valve seat, extending longitudinally in said housing and through said-bush- S.

4. In an engine of the character described, a frame providing a cylinder and a housing generally paralleling the cylinder, a cylinder head overlying one end of the cylinder and the corresponding end of the housing, said end of the housing being adapted to provide a valve seat, means within the housing near said valve seat providin a longitudinal tapered bore of a predetermined diameter at its convergent end, means within the housing and spaced from the first said means, providing a longitudinal tapered bore having a diameter at its divergent end less than said predetermined diameter at the convergent end of 1 the first said bore, tapered bushings received in said bores, and a valve stem having a valve head cooperaole with said valve seat, extending longitudinally in said housing and through said bushmgs.

5. In an engine of the character described, a frame providing a cylinder and a tubular housing adjacent th cylinder, a cylinder head overlying one end of the cylinder and the adjacent end of said housing, said housing end providing a valve seat, means integral with said housing forming correspondingly directed tapered seats within the housing, externally tapered bushings mounted in said tapered seats, one of said bushings having a maximum outer diameter less than the diameter at the convergent end of the tapered seat receiving another of the bushings, and a valve stem having a valve head cooperable with said valve seat, extending longitudinally in said housing and through said bushings.

6. The combination with an engine of the character described, providing a cylinder, a crankcase having an access opening at one side, and a camshaft in the crankcase near said access op ning, of a housing member arranged along said cylinder and open to the crankcase, a cylinder valve including a valve stem extending longitudinally in said housing, means including a cam on said camshaft, for actuating said valve, and means operatively supportin the valve stem in said housing, said last means comprising relatively spaced tapered seats in the housing, and tapered valve stem bushings frictionally received in said tapered seats, one of said bushings having its maximum outer diameter less than the minimum diameter of the tapered seat receiving another of the bushings.

7. The combination with an engine of the character described, providing a cylinder, a crankcase having an access opening at one side, and a camshaft in the crankcase near said access opening, of a housing member arranged along said cylinder and open to the crankcase, a cylinder valve including a valve stem extending longitudinally in said housing, means operatively supporting the valve stem in said housing, comprising relatively spaced, tapered seats in the housing and tapered valve stem bushings frictionally received in said seats, one of said seats having its maximum diameter less than the minimum diameter of the other seat, a cam on said camshaft, a cam follower between said cam and the end of said valve stem, and means carried by said crankcase providing an operative support for said follower.

8. The combination with an engine of the character described, providing a cylinder, a crankcase having an access opening at one side, and a camshaft in the crankcase near said access opening, of a housing member arranged along said cylinder and open to the crankcase, a cylinder valve including a valve stem extending longitudinally in said housing, means operatively supporting the valve stem in said housing, comprising relatively spacedtapered seat in the housing and tapered valve stem bushings frictionally received in said seats, one of said seats having its maximum diameter less than the minimum diameter of the other seat, a cam On said camshaft, a cylindrical cam follower between said cam and the end of said valve stem, and means providing a cylindrical seat slidably supporting said cam follower, the diameter of said seat being less than the minimum diameter of said one of said tapered seats.

9. A support for a cylinder valve of an internal combustion engine, comprising a tubular valve stem housing, means integral with the housing therein forming longitudinally spaced tapered seats, and valve stem guide bushings each of externally tapered form, frictionally received in said seats, said seats being tapered in the same direction and the maximum diameter of one seat being less than the minimum diameter of another of said seats.

10. In combination with the cylinder of an internal combustion engine, a cylinder valve including a valve stem, means carried by the cylinder and forming an enclosure for the valve stem, and means operatively supporting the valve stem in the enclosure, said last means comprising means integral with the enclosure therein providing relatively spaced tapered seats inwardly of the ends of the enclosure, and valve stem guide bushings each of externally tapered form, frictionally received in said seats, said seats being tapered in the same direction and the maximum diameter of one seat being less than the minimum diameter of the other seat.

FRANKLIN G. HOBART. 

